Pensée juive sur Le Lévitique 12:8

וְאִם־לֹ֨א תִמְצָ֣א יָדָהּ֮ דֵּ֣י שֶׂה֒ וְלָקְחָ֣ה שְׁתֵּֽי־תֹרִ֗ים א֤וֹ שְׁנֵי֙ בְּנֵ֣י יוֹנָ֔ה אֶחָ֥ד לְעֹלָ֖ה וְאֶחָ֣ד לְחַטָּ֑את וְכִפֶּ֥ר עָלֶ֛יהָ הַכֹּהֵ֖ן וְטָהֵֽרָה׃ (פ)

Si ses moyens ne lui permettent pas d’offrir un agneau, elle prendra deux tourterelles ou deux jeunes colombes, l’une pour holocauste, l’autre pour expiatoire; et le pontife fera expiation pour elle, et elle sera purifiée."

Guide for the Perplexed

The Levites did not sacrifice; they were not considered as being agents in the atonement of sins, for it was only the priest who was commanded “to make atonement for him” (Lev. 4:26) and “to make atonement for her” (Lev. 12:8). The duty of the Levites was the performance of vocal music; and a Levite became therefore disabled for service when he lost his voice. The object of the singing is to produce certain emotions; this object can only be attained by pleasing sounds and melodies accompanied by music, as was always the case in the Temple.